(1) Field of the Invention.
The present invention relates to locks, and particularly to locks adapted to be secured to the outer side of a roller shutter, in correspondence of its bottom or threshold extremity. The said locks present a bolt or shackle member which, in the lowered condition of the roller shutter, engages an anchoring ring secured to the threshold of the door or opening to be closed by the roller shutter.
(2) Statement of the Prior Art Known.
The following prior art is known to the applicants:
U.S. Pat. No. 3,581,530 (RASPADORI): the whole document.
U.S. Pat. No. 3,981,168 (VANELLI CORALLI et al.): the whole document.
U.S. patent application No. 886,502 filed Mar. 14, 1978, in the name of the same applicants as in the present case, having for title "Protected Padlock".